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Spacecraft reveal aurora near Jupiter’s south pole

Our solar system’s largest planet is big enough for massive light shows—one at each pole, new research reveals. Scientists already knew that Jupiter sported an aurora in its northern hemisphere—one that is permanent, large enough to swallow Earth, and hundreds of times brighter than the ephemeral glows our planet hosts at each pole. Now, a new analysis of data gleaned by Earth-orbiting x-ray telescopes in 2007 and 2016 reveals that the gas giant hosts a second aurora on its southern end. Earth’s magnetic field isn’t strong enough to generate an aurora at x-ray wavelengths. Unlike Earth’s auroras, Jupiter’s are not in sync, researchers report today in Nature Astronomy. Whereas the newly discovered southern hot spot (seen at infrared wavelengths by instruments on the Juno probe now orbiting Jupiter) pulses once every 9 to 11 minutes, the northern x-ray hot spot has, in the past, been observed pulsing at rates of once every 12 minutes, once every 26 minutes, and once every 40 to 45 minutes. Researchers aren’t quite sure why Jupiter’s auroras aren’t synchronized: Among some possibilities, the researchers say, the disparity could stem from the immense size or strength of the planet’s magnetic field, or may simply result from unexpected processes that help generate the auroras.